English: This is one of the few surviving film fragments from The Gulf Between (1917), the first Technicolor movie and the only one made to be publicly shown by the additive two-color method. The frame seen comes from an early experimental subtractive two-color printing test and only approximates the appearance of the image as it was originally projected. Each color frame began as a pair of frames of black-and-white film simultaneously photographed through red and blue-green filters in a special Technicolor movie camera. The frame pairs were on a single strip of film that ran through the camera at twice the normal rate. An ordinary black-and-white print was projected, also at twice the normal rate, using a special optical system that simultaneously projected each pair of frames through the appropriate color filters and superimposed them on the projection screen. In practice, maintaining acceptably good registration of the two images on the screen required constant attention by an expert, making the system commercially impractical. Subsequent two-color Technicolor films were issued as subtractive color prints with superimposed red and green dye images in each frame, eliminating the need for special projection equipment and unusual skills.